GC8 Engine Tear Down – Part 2

And on with part 2!

The special Subaru Cam gear tool was ordered and arrived, $120 later… Sadly if I had not stripped down the CNC for service and upgrades, I could have made one of these….

Semi plastic camgears…

Tool on and time to yeet it.

How does it work here you say?

Here it just pops inside the cam gear and works.

Unfortunately I didn’t have an impact 10MM hex for the bolts, I’ve been wanting a set for a while for these kinds of job, so a trip to Bunnings and I acquired this Kincrome set.

Two gears off.


Giving it a yeet.

And it rounded off… Hoorah!

Drilling time! The Milwaukee M12 drill does the job again and again.


This lets the cam gear off easily and just leaves the bolt core to be removed.

In this case, it wound off with fingers.

Cams out.

They look to still be in reasonable condition.

ARP nuts off and plonked the first head on the floor.

Interestingly one ARP stud has a lot of corrosion on it. I was going to reuse these but will likely just keep them for spares now.

Head gasket is in good condition.

Block is pretty filthy.

Pistons on this side have a bunch of carbon.

But nothing compared to our failure and award winner!
Lean n Mean Melty Piston!

That alloy is toasted.

No other cylinder shows any form of alloy speckling, so currently I’m assuming we have a fueling issue on this one. The fuel pressure regulator, injectors and fuel pump tested in the near future.

The bore suffered some serious damage to the liner.

The bottom has now been thrown on top of the wheel stack so we can pick the odd sensor and hose off it and swap it to the spare bottom end.

This explains the rebuild.

And with that, I ran out of garage time and knocked off for the day.
Next time we should be starting to put the engine back together using the spare block, the new gaskets/ARP studs and reusing the old heads.
We will also look at painting some of the bits and pieces, like coolant cross over pipe, the intake manifold, etc etc.